Electrical process control sensor assemblies

ABSTRACT

An electrical process control sensor assembly 10 for sensing a process or machine parameter, the assembly 10 including a sensor body 12 and a head 14, the body 12 defining a body interior 20. The assembly includes a sensing device 22 at least partially located in the body interior 20. The head 14 defines a head interior 24 which communicates with the body interior 20. The assembly 10 includes a connector arrangement 26 located in the head interior 24. The assembly 10 includes internal communicating members 28 extending between the sensing device 22 and the connector arrangement 26, the connector arrangement 26 connecting, in an installed condition, the internal communicating members 28 to external communicating members 30 to permit electrical communication therebetween. The head 14 defines a port 34 through which the external connecting members 30 are located in the installed condition. The assembly 10 includes a mounting 48 for mounting the head 14 to the body 12 which is arranged to permit adjustment of the orientation of the head 14 relative to the body 12.

This application is a continuation of U.S. application Ser. No.15/666,097 filed Aug. 1, 2017, which is a continuation of U.S.application Ser. No. 15/315,135 filed Nov. 30, 2016, both of which areincorporated herein by reference.

The present invention relates to electrical process control sensorassemblies, particularly, but not exclusively, electrical processcontrol sensor assemblies for sensing process or machine parameters.

Conventionally, electrical process control sensor assemblies areprovided for sensing process or machine parameters such asproximity/position, temperature, level, pressure, flow and movement of acomponent or material in a machine or process. For example, proximitysensor assemblies are used to confirm the open or closed position of avalve. Each sensor assembly can comprise a housing, a sensor devicewithin the housing, a mounting, and communication members in the form ofwires which extend from the sensor device to a separate connectorarrangement such as a junction box which is remote from the sensorassembly. The mounting can comprise a threaded formation formed orlocated on an external surface of the housing, which engages acorresponding thread of a support, the support comprising, for example,a bracket or machine casing.

In hazardous environments, electrical contacts have to be shielded fromexposure to potentially hazardous atmospheres and conventionally this isachieved by “potting” (i.e. encasing) the device and any exposedelectrical parts in an insulating filling within the assembly housing.The potting fixes and seals internal components and the communicationmembers to the sensor device and fills the remaining enclosed spacewithin the housing. Hazardous area standards require that the wholeassembly has to be capable of withstanding an external impact or aninternal ignition of gas, vapour or dust, and containing hot gas orvapour within the housing. The design of the assembly is also requiredto ensure that any escaping gas/vapour will have cooled whilst exitingalong a flame path out to the external atmosphere.

There are a number of problems with conventional arrangements. Oneproblem is that, if the wires are damaged, the whole sensor assemblymust be demounted and repaired or replaced. Another problem is that, inscrewing the housing into a tapped hole in the support, e.g. a block ormachine casing, the wires will rotate with the housing. This means thatwhenever the sensor assembly is mounted or demounted from the support,to prevent twisting and possible damage the wires have to bedisconnected at the separate junction box, which could be hundreds ofmeters away. A further problem is that, in installation, both the sensorassembly and the separate junction box must both be mounted andinterconnected with cables and glands.

According to a first aspect of the present invention, there is providedan electrical process control sensor assembly for sensing a process ormachine parameter, the assembly including a sensor body and a head, thebody defining a body interior, the assembly including a sensing deviceat least partially located in the body interior, the head defining ahead interior which communicates with the body interior, the assemblyincluding a connector arrangement located in the head interior, theassembly including internal communicating members extending between thesensing device and the connector arrangement, the connector arrangementconnecting, in an installed condition, the internal communicatingmembers to external communicating members to permit electricalcommunication therebetween, the head defining a port through which theexternal connecting members are located in the installed condition, theassembly including a mounting for mounting the head to the body which isarranged to permit adjustment of the orientation of the head relative tothe body.

Possibly, the sensing device is located entirely in the body interior.

Possibly, the connector arrangement is in a fixed association with thebody and the sensing device.

Possibly, the mounting is arranged to permit adjustment of theorientation of the head and the port relative to the body and theconnector arrangement.

Possibly, the connector arrangement is in a fixed association with thehead.

Possibly, the mounting is arranged to permit adjustment of theorientation of the head, the connector arrangement and the port relativeto the body.

Possibly, in the installed condition, the external communicating membersextend from the connector arrangement to external circuitry.

Possibly, the body extends along a body axis. Possibly, the port islocated on a lateral side of the head, relative to the body axis.

Possibly, the body includes a body housing, which may define the bodyinterior.

Possibly, the port is substantially planar, and may have a port axis,which may be normal to the plane of the port. Possibly, the port axis isnot aligned nor parallel with the body axis, and may substantially be at90° to the body axis.

Possibly, the mounting is arranged to permit rotation of the headrelative to the body, possibly around a mounting axis.

Possibly, the mounting is arranged to permit rotation of the head andthe port relative to the body and the connector arrangement, possiblyaround a mounting axis, and may permit adjustment of the circumferentialposition of the port relative to the connector arrangement around themounting axis. Possibly, the mounting axis is aligned with, and may becoincident with, the body axis.

Possibly, the mounting is arranged to permit rotation of the head, theconnector arrangement and the port relative to the body, possibly arounda mounting axis.

Possibly, the mounting includes a pair of correspondence surfaces. Onecorrespondence surface may be on the head and the other may be on thebody. Possibly, the correspondence surfaces substantially correspond insize and shape to each other and may be substantially in parallel.

Possibly, the correspondence surfaces define a passage therebetween.Possibly, the passage defines an escape path for fluid (e.g. vapourand/or gas, possibly including entrained dust) from the head interior toexternal ambient atmosphere.

Possibly, the passage includes a plurality of bends.

Possibly, each of the correspondence surfaces includes a plurality offaces.

Possibly, the correspondence surfaces are inclined relative to the bodyaxis. Possibly, the correspondence surfaces are curved.

Possibly, the mounting includes a seal, which may comprise a gasket or Oring, and which may substantially seal the passage to prevent fluid flowtherealong. Possibly, the mounting includes a seal formation whichdefines a seal channel, in which the seal may locate in an assembledcondition. Possibly, the seal formation comprises part of one of thefaces.

Possibly, the mounting includes a spigot formation, which may comprisepart of the head, and which may define a mouth.

Possibly, the mounting includes a socket formation, which may comprisepart of the body, and which may define a spigot receiving recess, whichmay receive the spigot formation in an assembled condition.

Possibly, the mounting includes a stem part of the body, which, in anassembled condition, may extend into the head interior, possibly throughthe mouth.

Possibly, the mounting includes a retainer, which may retain the head inan assembled condition relative to the body. Possibly, the retainerincludes a retaining formation, which defines a retaining channel.Possibly, the retaining formation comprises part of the stem part.Possibly, the retainer includes a retaining member, which may be in theform of a circlip, which may, in the assembled condition, locate in theretaining channel, and may locate substantially against an insideretaining surface of the spigot formation in the assembled condition.

Possibly, the connector arrangement is mounted to the stem part by aconnector mounting member.

Possibly, the connector arrangement is mounted to the inside of the headinterior by a connector mounting member.

Possibly, the connector arrangement includes a printed circuit board,and the internal communicating members may extend from the device to theprinted circuit board. Possibly, the assembly includes one or morefixing members which may extend between the printed circuit board andthe connector mounting member and may provide earth continuitytherebetween. Possibly, the connector arrangement includes connectorswhich may be mounted to the printed circuit board and may, in theinstalled condition, receive and retain the external communicatingmembers.

Possibly, the head includes a port formation, which may define the port.

Possibly, the head includes a head housing, which may define an accessaperture. Possibly, the head includes a cover, which may be movablebetween a closed condition, in which the cover closes the aperture, andan open condition, in which the cover permits access to the connectorarrangement through the aperture. Possibly, the head includes a seal forsealing between the cover and the head housing.

Possibly, the assembly is for sensing process or machine parametersincluding any of proximity, position, temperature, level, pressure, flowor movement of a component or material in a machine or process.Possibly, the sensor device is a device for sensing proximity, position,level, temperature, pressure or movement.

Possibly, the process or machine parameter is the proximity of anobject. Possibly, the sensing device is a proximity sensor for sensingthe proximity of an object. Possibly, the device comprises a magnetproximity sensor.

Possibly, the magnetic proximity sensor includes: a primary magnet, aprimary magnet holder, a flux sleeve, a flux sleeve holder, a centrehousing moulding containing a centre magnet located therein, aninsulation sleeve, a slider moulding with a shaft extending therefromand a bias slider magnet located therein, a contact carrier, a washer, aretaining plate, a screw, a contact moulding with first, second andthird contact pins extending therefrom, and a seal plug.

Possibly, the device comprises a reed assembly.

Possibly, the sensing device is a flow sensor for sensing the flow ofgas or liquid through a pipe or vessel. Possibly, the sensing device isa horizontal level sensor for sensing the level of a liquid in a tank.Possibly, the sensing device is a vertical level sensor for sensing thelevel of a liquid in a tank. Possibly, the sensing device is a vibrationsensor for sensing the movement of a body, for instance, acceleration,velocity or displacement of the body. Possibly, the sensing device is apressure sensor for sensing the pressure of a gas or liquid. Possibly,the sensing device is a temperature sensor for sensing the temperatureof a gas, liquid, or solid.

Possibly, the head defines a plurality of ports through which theexternal communicating members are located in the installed condition.Possibly, the head defines two ports on opposite sides of the head.Possibly, the head defines up to four equally spaced ports. Possibly,the ratio of connector arrangements to ports is 1:1, 1:2, 1:3 or 1:4.

Possibly, the internal communicating members are in the form of wires,spring contacts or brush contacts.

According to a second aspect of the present invention, there is provideda method of sensing a process or machine parameter, the method includingproviding an electrical process control sensor assembly, the assemblyincluding a sensor body and a head, the body defining a body interior,the assembly including a sensing device at least partially located inthe body interior, the head defining a head interior which communicateswith the body interior, the assembly including a connector arrangementlocated in the head interior, the assembly including internalcommunicating members extending between the sensing device and theconnector arrangement, the connector arrangement connecting, in aninstalled condition, the internal communicating members to externalcommunicating members to permit electrical communication therebetween,the head defining a port through which the external connecting membersare located in the installed condition, the assembly including amounting for mounting the head to the body which is arranged to permitadjustment of the orientation of the head relative to the body.

Possibly, the assembly includes any of the features described in any ofthe preceding statements or following description. Possibly, the methodincludes any of the steps described in any of the preceding statementsor following description.

Embodiments of the present invention will now be described, by way ofexample only, and with reference to the accompanying drawings, in which:

FIG. 1 is a schematic side view of a first sensor assembly in use whichincludes a magnetic proximity sensor;

FIG. 2 is a perspective view of the assembly of FIG. 1;

FIG. 3 is a perspective view from above of the first sensor assembly,partially disassembled, with a cover removed, looking into a headinterior;

FIG. 4 is a longitudinal side cross-sectional view of the first sensorassembly;

FIG. 5 is an exploded view of a part of the first sensor assembly;

FIG. 6 is a longitudinal side cross-sectional view of a second sensorassembly which includes a flow sensor;

FIG. 7 is a longitudinal side cross-sectional view of a third sensorassembly which includes a horizontal level sensor;

FIG. 8 is a longitudinal side cross-sectional view of a fourth sensorassembly which includes a vertical level sensor;

FIG. 9 is a longitudinal side cross-sectional view of a fifth sensorassembly which includes a vibration sensor;

FIG. 10 is a longitudinal side cross-sectional view of a sixth sensorassembly which includes a pressure sensor;

FIG. 11 is a longitudinal side cross-sectional view of a seventh sensorassembly which includes a temperature sensor;

FIG. 12 is a longitudinal side cross-sectional view of an eighth sensorassembly including a first alternative fluid path for escaping fluid;

FIG. 13 is a longitudinal side cross-sectional view of a ninth sensorassembly including a second alternative fluid path for escaping fluid;

FIG. 14 is a schematic side view of a tenth sensor assembly with a headwith two ports;

FIG. 15 is a longitudinal side cross-sectional view of an eleventhsensor assembly; and

FIG. 16 is a schematic side view of a part of the eleventh sensorassembly.

FIGS. 1 to 4 show a first electrical process control sensor assembly 10for sensing a process or machine parameter such as the proximity of anobject (not shown). The assembly 10 includes a sensor body 12 and a head14. The body 12 extends along a body axis 16 and defines a body interior20.

The assembly 10 includes a sensing device 22 located in the bodyinterior 20.

The head 14 defines a head interior 24 which communicates with the bodyinterior 20.

The assembly 10 includes a connector arrangement 26 located in the headinterior 24 and in a fixed association with the body 12 and the sensingdevice 22. The assembly 10 includes internal communicating members 28extending between the sensing device 22 and the connector arrangement26. The connector arrangement 26 connects, in an installed condition,the internal communicating members 28 to external communicating members30 to permit electrical communication therebetween.

The head 14 defines a port 34 through which the external connectingmembers 30 are located in the installed condition.

The assembly 10 includes a mounting 48 for mounting the head 14 to thebody 12 which is arranged to permit adjustment of the orientation of thehead 14 and the port 34 relative to the body 12 and the connectorarrangement 26.

In the installed condition, the external communicating members 30 extendfrom the connector arrangement 26 to external circuitry 32.

In some examples of the disclosure, the sensing device 22 could be aproximity sensor and could comprise a magnet assembly or a reedassembly, for sensing the proximity of an object.

In the example of the disclosure shown in FIG. 4 the sensing device 22is a proximity sensor 22 with a magnetic assembly, known as a magneticproximity sensor.

An exploded view of the magnetic proximity sensor 22 is shown in FIG. 5.With reference to FIGS. 4 and 5, the magnetic proximity sensor 22includes: a primary magnet 134, a primary magnet holder 136, a fluxsleeve 138, a flux sleeve holder 140, a centre housing moulding 142containing a centre magnet 144 (not shown) located therein, aninsulation sleeve 146, a slider moulding 148 with a shaft 150 extendingtherefrom and a bias slider magnet 152 (not shown) located therein, acontact carrier 154, a washer 156, a retaining plate 158, a screw 160, acontact moulding 162 with first 164, second 166 and third 168 contactpins extending therefrom, and a seal plug 170.

In some examples of the disclosure, the magnetic proximity sensor may beprovided without a flux sleeve.

As shown in FIG. 4, the magnetic proximity sensor 22 is located entirelywithin the body interior 20.

The body 12 extends along a body axis 16.

The head 14 includes a port formation 94, which defines the port 34. Theport 34 is substantially planar, and has a port axis 36, which in theexample shown is normal to the plane of the port 34. In the exampleshown in FIGS. 1 to 4, the port axis 36 is not aligned with nor inparallel to the body axis 16 and is substantially at 90° to the bodyaxis 16. The port 34 is located on a lateral side of the head 14,relative to the body axis 16.

The mounting 48 is arranged to permit rotation of the head 14 and theport 36 relative to the body 12 and the connector arrangement 26 arounda mounting axis 130, which in this example, is aligned with, and iscoincident with, the body axis 16. The mounting 48 permits adjustment ofthe circumferential position of the port 34 relative to the connectorarrangement 26 around the mounting axis 130.

The head 14 includes a head housing 38, which defines an access aperture40. The head 14 includes a cover 42, which is movable between a closedcondition, in which the cover 42 closes the aperture 40, and an opencondition, in which the cover 42 permits access to the connectorarrangement 26 through the aperture 40.

The head 14 includes a seal 44 for sealing between the cover 42 and thehead housing 38. The cover 42 and/or the head housing 38 could define aseal recess 46 in which the seal 44 is located in an assembledcondition. The cover 42 and the head housing 38 could includecorresponding mutually engageable threaded formations 114.

The head 14 includes a cover lock 110 for securing the cover 42 to thehousing 38. The cover lock 110 includes a lock member 112, which couldbe in the form of a grub screw, which, in the assembled condition,extends through a threaded cover lock aperture 114 defined by the headhousing 38 to locate against the cover 42 to prevent the cover 42unintentionally moving from the assembled condition, for example, byvibration.

The mounting 48 includes a pair of correspondence surfaces 50. Onecorrespondence surface 50A is on the head 14 and the othercorrespondence surface 50B is on the body 12. The correspondencesurfaces 50 substantially correspond in size and shape to each other andare substantially in parallel.

The correspondence surfaces 50 define a passage 52 therebetween. Thepassage 52 defines a fluid path for escaping fluid (e.g. vapour and/orgas, which could include entrained dust) from the head interior 24 toexternal ambient atmosphere 54.

In the example of the disclosure shown in FIG. 4, the passage 52includes a plurality of bends 56. The passage 52 includes three bends56. Each bend 56 is of substantially 90°. The passage 52 includesstraight parts 58 when viewed in longitudinal cross section (i.e. incross section taken along the length of the assembly 10) as shown inFIG. 4. The passage 52 has a height dimension 60, which provides a gap61 between the correspondence surfaces 50. Each of the correspondencesurfaces 50 includes a plurality of faces 62, which are located betweenthe bends 56.

The mounting 48 includes a spigot formation 70, which comprises part ofthe head 14, and defines a mouth 72. The head correspondence surfaces50A comprise surfaces of the spigot formation 70.

The mounting 48 includes a socket formation 74, which comprises part ofthe body 12, and which defines a spigot receiving recess 76, whichreceives the spigot formation 70 in the assembled condition. The bodycorrespondence surfaces 50B comprise surfaces of the socket formation74.

The mounting 48 includes a stem part 78 of the body 12, which in theassembled condition extends into the head interior 24, through the mouth72.

The mounting 48 includes a passage seal 64, which could comprise agasket or O ring, and which substantially seals the passage 52 toprevent fluid flow therealong. The mounting 48 includes a passage sealformation 66 which defines a seal channel 68, in which the seal 64 islocated in the assembled condition. The seal formation 66 comprises partof one of the faces 62. In the example shown, the seal formation 66comprises part of the innermost face 62B of the body correspondencesurface 50B which is also a surface of the stem part 78 of the body 12.

The mounting 48 includes a retainer 80, which retains the head 14 in anassembled condition relative to the body 12. The retainer 80 includes aretaining formation 82 which defines a retaining channel 84. Theretaining formation 82 comprises part of the stem part 78. The retainer80 includes a retaining member 86, which could be in the form of acirclip, which locates in the retaining channel 84 substantially againstan inside retaining surface 88 of the spigot formation 70 in theassembled condition. In the assembled condition, the retaining formation82 prevents movement of the spigot formation 70 out of the spigotreceiving recess 76 and thus retains the head 14 in engagement with thebody 12.

The connector arrangement 26 is mounted to an end of the stem part 78 ofthe body 12 by a connector mounting member 126, which provides the fixedassociation between the connector arrangement 26, the body 12 and thesensing device 22. The connector arrangement 26 includes a printedcircuit board 90, which is fixed to the connector mounting member 126 byfixing members 128. The fixing members 128 provide earth continuitybetween the connector mounting member 126 and the printed circuit board90.

The internal communicating members 28 extend from the sensing device 22to the printed circuit board 90. The connector arrangement 26 includesconnectors 92 (for example, clamp connectors) which are mounted to theprinted circuit board 90 and in use, in an installed condition, receiveand retain the external communicating members 30.

The assembly 10 includes a head lock 104 for securing the head 14 in afixed circumferential position relative to the body 12. The head lock104 includes a lock member 106, which could be in the form of a grubscrew, which, in the assembled condition, extends through a threadedhead lock aperture 108 defined by the head housing 38 to locate againstthe stem part 78 to prevent the head 14 moving relative to the body 12.

The port formation 94 includes a threaded formation 122 engageable inthe assembled condition with a corresponding threaded formation of acable gland (not shown).

The body 12 includes a body housing 18, which defines the body interior20. The body housing 18 includes a threaded formation 124 on an externalsurface for mounting to a support 100. The body housing 18 includes apair of oppositely directed, parallel flat surface areas 132.

In one example, the body housing 18, the head housing 38 and the cover42 are formed of a metal such as stainless steel. The correspondencesurfaces 50 could be formed of a self-lubricating bush/bearing material.

To enable relative movement between the head 14 and the body 12, theremust be some clearance between the correspondence surfaces 50. To meetthe requirements for hazardous environments, the assembly 10 must beable to withstand an internal ignition of gas, vapour or dust, andcontain hot gas or vapour within the assembly 10, or allow it to coolbefore exiting into a potentially explosive external atmosphere.

In one example, the applicant has found that these requirements can bemet by providing a passage 52 with a gap 61 of no more than 0.02 mm andat least one straight part 58 with a length of at least 6.35 mm.

In another example, the applicant has found that these requirements canbe met by providing a passage 52 with a gap 61 of no more than 0.1 mmand at least one straight part 58 with a length of at least 6.00 mm.Thus, one of the faces 62 of the correspondence surfaces 50 has astraight length in longitudinal cross section of at least 6 mm.

In use, and referring to FIG. 1, the sensor assembly 10 is threadablymounted to the support 100 by a screwing action, using a spanner inengagement with the flat surface areas 132 to prevent damage to the headlock 104. The cover 42 is removed from the body housing 18. The head 14is rotated relative to the body 12 to a convenient position and lockedwith the head lock 104. The external communicating members 30 arelocated through the cable gland and the port 34 and connected to theconnectors 92. The gland can then be tightened to seal the port 34 andthe cover 42 located onto the head housing 38 and locked with the coverlock 110.

Advantageously, the sensor assembly 10 permits disconnection andreconnection of the external communicating members 30 without requiringremoval of the sensor body 12 from the support 100. The orientation ofthe head 14 and the port 34 can be adjusted relative to the body 12 andthe connector arrangement 26. Thus the orientation of the head 14 andthe port 34 can be adjusted to optimise the cable entry position intothe head 14 for a particular installation. The assembly 10 can bemounted without disconnection of the external communicating members 30from the external circuitry 32.

Advantageously, the mounting 48 provides a fluid escape path defined bythe passage 72 which permits use of the assembly 10 in hazardousenvironments.

FIGS. 6 to 11 respectively show second, third, fourth, fifth, sixth andseventh electrical process control sensor assemblies 200, 300, 400, 500,600, 700 for sensing a process or machine parameter.

Many features of the second, third, fourth, fifth, sixth and seventhelectrical process control sensor assemblies 200, 300, 400, 500, 600,700 are similar to those previously described, and where features arethe same or similar the same reference numerals have been used and thesefeatures will not be described again for the sake of brevity. In fact,the only differences relative to the first electrical process controlsensor assembly are as follows.

In the second electrical process control sensor assembly 200 shown inFIG. 6, the sensing device 22 is a flow sensor. The flow sensor 22 isused to sense the flow of fluid (gas or liquid) through a pipe orvessel. The flow sensor 22 includes a sensor element 172 and an actuator174 in the form of a paddle coupled to the sensor element 172 by adetection means 176. A part of the actuator 174 extends from the bodyinterior 20. The sensing device 22 is therefore partially located in thebody interior 20. In some examples of the disclosure, the detectionmeans 176 includes a spring and piston arrangement 178.

In the third electrical process control sensor assembly 300 shown inFIG. 7, the sensing device 22 is a horizontal level sensor. Thehorizontal level sensor 22 is used to sense the level of a fluid in atank. The horizontal level sensor 22 includes a sensor element 172 andan actuator 174 in the form of a float coupled to the sensor element 172by a detection means 176. A part of the actuator 174 extends from thebody interior 20. The sensing device 22 is therefore partially locatedin the body interior 20. In some examples of the disclosure, thedetection means 176 includes a spring and piston arrangement 178.

In the fourth electrical process control sensor assembly 400 shown inFIG. 8, the sensing device 22 is a vertical level sensor. The verticallevel sensor 22 is used to sense the level of a fluid in a tank. Thevertical level sensor 22 includes a sensor element 172 and an actuator174 in the form of a float. A part of the actuator 174 extends from thebody interior 20. The sensing device 22 is therefore partially locatedin the body interior 20.

In the fifth electrical process control sensor assembly 500 shown inFIG. 9, the sensing device 22 is a vibration sensor. The vibrationsensor 22 is used to sense the movement of a body, for exampleacceleration, velocity or displacement of the body. The vibration sensor22 includes a sensor element 172 and a detection means 176 in the formof an opening for receiving a stud (not shown), as would be understoodby a person skilled in the art.

In the sixth electrical process control sensor assembly 600 shown inFIG. 10, the sensing device 22 is a pressure sensor. The pressure sensor22 is used to sense the pressure of fluid (gas or liquid). The pressuresensor 22 includes a sensor element 172 and a detection means 176 in theform of a spring and piston arrangement 178, as would be understood by aperson skilled in the art.

In the seventh electrical process control sensor assembly 700 shown inFIG. 11, the sensing device 22 is a temperature sensor. The temperaturesensor 22 is used to sense the temperature of a fluid (gas or liquid),or solid. The temperature sensor 22 includes a sensor element 172 whichextends from the body interior 20. The sensing device 22 is thereforepartially located in the body interior 20.

FIGS. 12 and 13 respectively show eighth and ninth electrical processcontrol sensor assemblies 800, 900 for sensing a process or machineparameter.

Many features of the eighth and ninth electrical process control sensorassemblies 800, 900 are similar to those previously described, and wherefeatures are the same or similar the same reference numerals have beenused and these features will not be described again for the sake ofbrevity. In fact, the only differences relative to the electricalprocess control sensor assemblies already described above are asfollows.

In the eighth electrical process control sensor assembly 800 shown inFIG. 12, a serrated fluid path 180 is provided in which thecorrespondence surfaces 50 are inclined relative to the body axis. Thecorrespondence surfaces 50 substantially correspond in size and shape toeach other and are substantially in parallel.

The correspondence surfaces 50 define a passage 52 therebetween. Thepassage 52 defines a fluid path for escaping fluid (e.g. vapour and/orgas, which could include entrained dust) from the head interior 24 toexternal ambient atmosphere 54.

In one example, the passage 52 has a height dimension of no more than0.02 mm and an overall length of at least 6.35 mm. In another example,the passage 52 has a height dimension of no more than 0.01 mm and anoverall length of at least 6.00 mm.

In the ninth electrical process control sensor assembly 900 shown inFIG. 13, a sinusoidal fluid path 182 is provided in which thecorrespondence surfaces 50 are curved. The correspondence surfaces 50substantially correspond in size and shape to each other and aresubstantially in parallel.

The correspondence surfaces 50 define a passage 52 therebetween. Thepassage 52 defines a fluid path for escaping fluid (e.g. vapour and/orgas, which could include entrained dust) from the head interior 24 toexternal ambient atmosphere 54.

In one example, the passage 52 has a height dimension of no more than0.02 mm and an overall length of at least 6.35 mm. In another example,the passage 52 has a height dimension of no more than 0.01 mm and anoverall length of at least 6.00 mm.

FIG. 14 shows a tenth electrical process control sensor assembly 1000for sensing a process or machine parameter.

Many features of the tenth electrical process control sensor assembly1000 are similar to those previously described, and where features arethe same or similar the same reference numerals have been used and thesefeatures will not be described again for the sake of brevity. In fact,the only differences relative to the electrical process control sensorassemblies already described above are as follows.

In the example shown in FIG. 14 the head 14 defines two ports 34 onopposite sides of the head. In other examples of the disclosure the head14 defines up to four equally spaced ports 34. The ratio of connectorarrangements 26 to ports 34 could be 1:1, 1:2, 1:3 or 1:4.

FIGS. 15 and 16 show an eleventh electrical process control sensorassembly 1100 for sensing a process or machine parameter.

Many features of the eleventh electrical process control sensor assembly1100 are similar to those previously described, and where features arethe same or similar the same reference numerals have been used and thesefeatures will not be described again for the sake of brevity. In fact,the only differences relative to the electrical process control sensorassemblies already described above are as follows.

The connector arrangement 26 of the eleventh sensor assembly 1100 is ina fixed association with the head 14. The assembly 1100 includes amounting 48 for mounting the head 14 to the body 12 which is arranged topermit adjustment of the orientation of the head 14, the port 34 and theconnector arrangement 26 relative to the body 12 and the sensing device22.

The connector arrangement 26 includes a first printed circuit board 90,which is fixed to a connector mounting member 126. The connectormounting member 126 is mounted to the inside of the head interior 24 bya threaded connection, which provides the fixed association between theconnector arrangement 26 and the head 14.

The assembly 1100 includes a second printed circuit board 184, which isfixed to a mounting member 186. The mounting member 186 is fixed to thetop side of the body 12 by a threaded connection. The second printedcircuit board 184 is connected to the sensing device 22 by internalcommunicating wires (not shown).

The assembly 1100 includes internal communicating members 28 extendingbetween the first and second printed circuit boards 90, 184. Theinternal communicating members 28 therefore connect the sensing device22 with the connector arrangement 26.

In the example of the disclosure shown in FIG. 16 the internalcommunicating members 28 are a plurality of spring contacts 188. Inother examples of the disclosure a single spring contact 188 may beprovided. With respect to each spring contact 188, a first part 190 ofthe spring contact 188 is fixedly connected to the second printedcircuit board 184, and a second part 192 of the spring contact 188 isurged against a copper track 194 laid on the underside of the firstprinted circuit board 90 to thereby make an electrical contact betweenthe sensing device 22 and the connector arrangement 26.

Adjustment of the orientation of the head 14, the port 34 and theconnector arrangement 26 relative to the body 12 and the sensing device22 by rotation causes the second part 192 of the spring contact 188 tomove along the copper track 194 laid on the underside of the firstprinted circuit board 90 such that electrical contact between thesensing device 22 and the connector arrangement 26 is maintained in anyorientation of the head 14 relative to the body 12.

The resistance between the spring contacts 188 and the copper track 194is sufficient to maintain electrical contact during rotation of the head14 relative to the body 12 without having a noticeable effect on theamount of force required to rotate the head 14 relative to the body 12.

A further advantage of the assembly 1100 is that the orientation of theconnector arrangement 26 relative to the port 34 is fixed in an optimumposition to allow, in an installed condition, external communicatingmembers 30 to extend through the port 34 and connect to the connectorarrangement 26. Accordingly, the relative positions of the connectorarrangement 26 and the port 34 remain constant throughout adjustment ofthe orientation of the head 14 relative to the body 12.

In other examples of the disclosure, the internal communicating members28 may be in the form of brush contacts (not shown) which would extendfrom the first printed circuit board 90 and make contact with coppertracks 194 laid on the upper side of the second printed circuit board184.

The spring and brush contacts allow unlimited rotation of the head 14about the body 12.

Alternatively, the internal communicating members 28 extending betweenthe first and second printed circuit boards 90, 184 may be in the formof wires of a sufficient length to allow the head 14 to be rotated aboutthe body 12, for instance, by at least 360 degrees. The degree ofrotation permitted may be controlled by a stop (not shown) beingprovided on the head 14 or body 12 to prevent rotation by more than 360degrees. Various other modifications could be made without departingfrom the scope of the invention. The assembly and the various componentsthereof could be of any suitable size and shape, and could be formed ofany suitable material (within the scope of the specific definitionsherein).

There are thus provided sensor assemblies with a number of advantagesover conventional arrangements.

Features described in the preceding description may be used incombinations other than the combinations explicitly described.

Although functions have been described with reference to certainfeatures, those functions may be performable by other features whetherdescribed or not.

Although features have been described with reference to certainexamples, those features may also be present in other examples whetherdescribed or not.

Whilst endeavouring in the foregoing specification to draw attention tothose features of the invention believed to be of particular importanceit should be understood that the Applicant claims protection in respectof any patentable feature or combination of features hereinbeforereferred to and/or shown in the drawings whether or not particularemphasis has been placed thereon.

1. An electrical process control sensor assembly for sensing a processor machine parameter, the assembly including a sensor body and a head,the body defining a body interior, the assembly including a sensingdevice at least partially located in the body interior, the headdefining a head interior which communicates with the body interior, theassembly including a connector arrangement located in the head interior,the assembly including internal communicating members extending betweenthe sensing device and the connector arrangement, the connectorarrangement connecting, in an installed condition, the internalcommunicating members to external communicating members to permitelectrical communication therebetween, the head defining a port throughwhich the external connecting members are located in the installedcondition, the assembly including a mounting for mounting the head tothe body, the mounting being arranged to permit rotation of the headrelative to the body around a position on a mounting axis.
 2. Anassembly according to claim 1, in which the body extends along a bodyaxis and the mounting axis is aligned with the body axis, wherein themounting is arranged such that rotation of the head relative to the bodyaround the position on the mounting axis is permitted without linearmovement of the head or the body along the mounting axis.
 3. An assemblyaccording to claim 1, in which the mounting is arranged to permitcontinuous rotation of the head relative to the body around the positionon the mounting axis.
 4. An assembly according to claim 1, in which theport is located on a lateral side of the head, relative to the bodyaxis, wherein the port is substantially planar, and has a port axis,which is normal to the plane of the port.
 5. An assembly according toclaim 4, in which the port axis is substantially at 90° to the bodyaxis.
 6. An assembly according to claim 1, in which the head defines aplurality of ports through which the external communicating members arelocated in the installed condition.
 7. An assembly according to claim 1,in which the connector arrangement is in a fixed association with thebody and the sensing device, and the mounting is arranged to permitrotation of the head and the port relative to the body and the connectorarrangement around the position on the mounting axis.
 8. An assemblyaccording to claim 1, in which the connector arrangement is in a fixedassociation with the head, and the mounting is arranged to permitrotation of the head, the connector arrangement and the port relative tothe body around the position on the mounting axis.
 9. An assemblyaccording to claim 1, in which the mounting includes a spigot formationand a socket formation, the socket formation defining a spigot receivingrecess, which receives the spigot formation in an assembled condition,wherein the spigot formation comprises part of the head and the socketformation comprises part of the body.
 10. An assembly according to claim9 in which the spigot formation defines a mouth, and the mountingincludes a stem part of the body, which, in an assembled condition,extends into the head interior, through the mouth.
 11. An assemblyaccording to claim 1, in which the mounting includes a retainer, whichretains the head in an assembled condition relative to the body.
 12. Anassembly according to claim 11, in which the retainer includes aretaining formation, which defines a retaining channel.
 13. An assemblyaccording to claim 11, in which the spigot formation defines a mouth,and the mounting includes a stem part of the body, which, in anassembled condition, extends into the head interior, through the mouth,and the retaining formation comprises part of the stem part.
 14. Anassembly according to claim 11, in which the retainer includes aretaining member, which, in the assembled condition, locates in theretaining channel.
 15. An assembly according to claim 14, in which themounting includes a spigot formation and a socket formation, the socketformation defining a spigot receiving recess, which receives the spigotformation in an assembled condition, wherein the spigot formationcomprises part of the head and the socket formation comprises part ofthe body, wherein the retaining member locates substantially against aninside retaining surface of the spigot formation in the assembledcondition.
 16. An assembly according to claim 1, in which the assemblyis for sensing process or machine parameters including any of proximity,position, temperature, level, flow, pressure or movement of a componentor material in a machine or process.
 17. An assembly according to claim1, in which the sensor is a magnetic proximity sensor.
 18. An assemblyaccording to claim 17, in which the magnetic proximity sensor includes:a primary magnet, a primary magnet holder, a flux sleeve, a flux sleeveholder, a centre housing moulding containing a centre magnet locatedtherein, an insulation sleeve, a slider moulding with a shaft extendingtherefrom and a bias slider magnet located therein, a contact carrier, awasher, a retaining plate, a screw, a contact moulding with first,second and third contact pins extending therefrom, and a seal plug. 19.A method of sensing a process or machine parameter, the method includingproviding an electrical process control sensor assembly for sensing aprocess or machine parameter, the assembly including a sensor body and ahead, the body defining a body interior, the assembly including asensing device at least partially located in the body interior, the headdefining a head interior which communicates with the body interior, theassembly including a connector arrangement located in the head interior,the assembly including internal communicating members extending betweenthe sensing device and the connector arrangement, the connectorarrangement connecting, in an installed condition, the internalcommunicating members to external communicating members to permitelectrical communication therebetween, the head defining a port throughwhich the external connecting members are located in the installedcondition, the assembly including a mounting for mounting the head tothe body, the mounting being arranged to permit rotation of the headrelative to the body around a position on a mounting axis.
 20. Anelectrical process control sensor assembly for sensing a process ormachine parameter, the assembly including a sensor body and a head, thebody defining a body interior, the assembly including a sensing deviceat least partially located in the body interior, the assembly includinga mounting for mounting the head to the body, the mounting beingarranged to permit rotation of the head relative to the body around aposition on a mounting axis.